The presence of hydrogen sulfide in natural gas, liquid petroleum gas (LPG), and even in crude petroleum has led to a need to determine hydrogen sulfide concentrations in different samples. H2S detection that is fast and reliable is the cornerstone of many industrialized processes that cannot tolerate H2S in their gas due to fatal consequences for humans and degradation of physical assets such as pipelines.
To determine hydrogen sulfide concentrations, the chemical reaction
is used. This reaction is implemented by using paper tape impregnated or covered with lead acetate. The paper tape is immersed in a liquid bath with lead acetate, thereby leaving the paper capable of detecting H2S. Instead of hydrogen sulfide concentration, the same reaction can be used to determine total sulfur concentration by mixing the sample gas with hydrogen then heating the resulting gas to approximately 900 C where all sulphurs are changed into H2S.
The above processes are well-known and are detailed in U.S. Pat. Nos. 4,127,780 and 5,206,519. The contents of these documents are hereby incorporated in its entirety by reference.
The issue with current testing equipment is that, currently, only one side of the testing tape is used. This leads to waste and inefficiencies as each sensing tape is only used once and is then discarded. As well, due to the cost of a single analyzer of the above type, most users that require analysis on more than one stream of gas will utilize a stream switching technique on a single analyzer rather than purchasing multiple analyzers. Stream switching implies that the stream(s) currently not being analyzed can encounter a rise in the H2S concentration to unacceptable levels and this rise in H2S concentration may be undetected.